As California's top-level investigative law enforcement agency & legal department, CA DOJ has statewide authority with over 4700 employees (approximately 1100 being state attorneys) and a budget of $754 million.[2] The department has a long history within the state, and its law enforcement personnel have a reputation of being some of the best in the country. Besides its support of the California Attorney General, the department is frequently mentioned in the newsmedia for (among other activities):

Its assistance to federal law enforcement agencies, for example, CA DOJ Special Agents working alongside their federal counterparts on cases and while federalized on several different task forces.

Its forensic laboratory work that processes evidence from multiple agencies throughout the state.

An aerial shot of California Department of Justice Special Agents posing with several CA DOJ vehicles and aircraft.

The sworn law enforcement personnel of CA DOJ (primarily assigned to the Division of Law Enforcement), consists of approximately 500 law enforcement officers (Special Agents). They make up a group a criminal investigators with varied backgrounds in law enforcement and intelligence agencies. This small, but elite, group of sworn peace officers are generally better educated and more experienced than many of their law-enforcement counterparts, and are often called upon for their expertise and ability to coordinate joint activities between local, state, and federal agencies throughout the state. Special Agents are a force multiplier, assisting agencies with expertise, equipment and personnel. Whether running a narcotic task force, investigating a murder, uncovering political corruption, or disrupting violent gangs, CA DOJ Special Agents consistently conduct a variety of law enforcement investigative activities at multiple levels. Additionally, CA DOJ Special Agents are often federally deputized/cross-sworn as federal agents in order to allow them to complete cases outside of California or to participate in federal task forces. They are also frequently chosen by their peer agencies as the lead group in multi-jurisdictional cases. Small and large law enforcement agencies within California can request assistance from CA DOJ as necessary in today's tight economic realities.[5]

While the California Office of the Attorney General was created in 1850, the law enforcement and criminal investigative capabilities of the CA DOJ were not fully established until the early 20th century. However, the mission of CA DOJ Special Agents mirrors that of the original California Rangers; the first statewide criminal investigative and law enforcement agency created on May 17, 1853. Although the California Rangers were quickly disbanded (following their success in bringing the violent Five Joaquins gang to justice), their special law enforcement capabilities and statewide investigative mission now reside primarily within the Special Agents of CA DOJ.[6]

The Division of Law Enforcement ("CA DOJ DLE") is the primary law enforcement branch of the California Department of Justice. The division is not only the largest within the department, but also one of the largest statewide investigative law enforcement agencies in the United States. Its staff consists of sworn law enforcement officers (Special Agents), criminalists/forensic scientists, analysts, and other professional personnel. The primary mission of the Division of Law Enforcement is to enhance public safety by conducting criminal investigations, regulatory oversight, and forensic analysis of evidence for criminal proceedings. The division also assists local, state and federal agencies by providing services in specialized areas including:

The California Bureau of Investigation (CBI), was established in 1927 as the Division of Criminal Investigations, with the now disbanded California Bureau of Narcotic Enforcement (BNE). The CBI provides statewide expert investigative services through special agents combating multi-jurisdictional criminal organizations, and also operates several programs including a Special Investigations Team (SIT) handling high-profile investigations, the state task force program, a Special Operations unit, LA CLEAR, and the state anti-terrorism program. As the state's FBI counterpart, the CBI investigates a wide-variety of crimes including homicides, fraud, sexual predators, violent/repeat offenders, serial crimes, internet crimes against children, money laundering, extortion, public corruption, rapes, false imprisonment, terrorism, and much more.

The California Bureau of Firearms (BOF), "is responsible for identifying individuals who are ineligible to acquire or possess firearms" and other weapons, primarily targeting felons and others that may be in possession of illegal weapons/explosives. The BOF conducts a variety of operations, including undercover investigations for violations of state firearms laws, training local law-enforcement officials on firearms law and regulations, inspecting licensed firearms dealers, lending safety assistance to gun show promoters, locating and arresting felons in possession of firearms, and testifying as expert witnesses. The BOF also works closely with its federal counterparts in the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF).

The California Bureau of Gambling Control (BGC) "regulates legal gambling activities." The BGC investigates casinos and card clubs throughout California for violations of California's gaming laws. Violation of state gaming laws by casinos and clubs as well as their employees and customers are the focus of most BGC investigations. They also investigate complex thefts, robberies, scams and other crimes related to the casinos and clubs.

The California Bureau of Forensic Services (BFS) is the scientific arm of the department, whose mission is to serve the people of California on behalf of the Attorney General's Office with state of the art forensic services throughout the state. Forensic scientists collect, analyze, and compare physical evidence from suspected crimes via some of the most well-equipped and accredited forensic science laboratories in the country.

The California Bureau of Medi-Cal Fraud & Elder Abuse (BMFEA) protects California's most vulnerable citizens and helps to safeguard the state's Medi-Cal program. The Bureau of Medi-Cal Fraud and Elder Abuse works aggressively to investigate and prosecute those who rob taxpayers of millions of dollars each year and divert scarce health care resources from the needy. The BMFEA is funded via an $18.6 million federal grant program. The Bureau conducts statewide investigations and prosecutes fraud relating to the activities of medical providers receiving funding under the Medi-Cal system. The section also reviews and prosecutes reports of elder abuse and neglect of patients housed in federally funded nursing home facilities.

The Appeals, Writs and Trials Section handles post-conviction proceedings. This involves prosecuting felony criminal appeals in state court, responding to petitions for writs of habeas corpus in state and federal courts, and prosecuting death penalty appeals. Deputies also handle criminal investigations, conduct evidentiary hearings, appear in local courts to litigate recusal motions, and prosecute felonies in cases in which the local county district attorney has been recused or otherwise removed from the case. Deputies appear regularly in the California Court of Appeal, California Supreme Court, United States District Court, and Ninth Circuit Court of Appeals, and occasionally in the United States Supreme Court.

The Correctional Writs & Appeals Section represents the state in civil rights actions involving state prisoners. This section also represents the Department of Corrections, Board of Prison Terms, Youth Authority and the Department of Mental Health and their employees in cases regarding policies, practices or conditions of confinement of inmates.

The Office of Native American Affairs serves as liaison and addresses justice-related issues for California's Indian citizens who reside on reservations, rancherias and in urban communities for the overall improvement of the quality of life for Indian people.

The Financial Fraud and Special Prosecutions Unit investigates and prosecutes complex criminal cases occurring in California, primarily related to financial, securities, mortgage, and environmental fraud; public corruption, including violations of California's Political Reform Act; “underground economy” offenses, including tax and revenue fraud and counterfeiting; transnational organized crime; human trafficking; and crimes within the scope of the Attorney General's Bureau of Children's Justice. Vertical teams of prosecutors, investigators, auditors, and paralegals often work with federal and local authorities on cases involving multi-jurisdictional criminal activity.

The Research Advisory Panel primarily seeks to ensure the safety and protection of participating human research subjects and adequate security of the controlled substances used in the study. The Panel Members evaluate the scientific validity of each proposed project, and may reject proposals where the research is poorly conceived, would produce conclusions of little scientific value, or would not justify the exposure of California subjects to the risk of research.

The Division of Civil Law "both prosecutes and defends civil actions." The overall mission of the Civil Law Division is to provide skilled legal services to state agencies and officials in trial and appellate litigation which includes prosecuting and defending matters in state and federal courts and before various administrative tribunals.

A fictional unit within CA DOJ operating under the California Bureau of Investigation (CBI), was featured for seven seasons in the television seriesThe Mentalist. This unit of CBI focused mostly on the investigation of homicides, and occasionally kidnappings or missing persons. The Region 1 DVD release of the fourth season of The Mentalist includes the special feature CBI: Behind the Badge, focusing on the interaction of real-life law enforcement officers in California, including some within the CBI, with those who tutored those who worked on the program in providing a realistic portrayal.[8]

CBI was also referenced in one episode of the crime television series Numb3rs, where a CBI agent worked together with the FBI.[9]

Beginning in 2008 (with the most recent written in 2016), New York Times best selling author Jeffery Deaver wrote a series of crime drama novels starring the fictional Special Agent Kathryn Dance of the CA DOJ/CBI.